Advent of Code 2025

It's really disheartening that the culture has changed so much someone would think doing AoC puzzles just for the fun of it is an unpopular stance :(

Doing things for the fun of it, for curiosity's sake, for the thrill of solving a fun problem - that's very much alive, don't worry!

While is „only“ 12 days, are like 24 challenges. As no leaderboard is there, and I do it for fun, i will do it in 24 days.

I never liked the global leaderboard since I was usually asleep when the puzzles were released. I likely never would have had a competitive time anyway.

I used MATLAB last year while I was re-learning it for work. It did okay, but we didn't have a license for the Image Processing Toolbox, which has a boatload of tools for the grid based problems.

My personal choice is always Common Lisp. Absolute swiss army knife.

Go is strong. You get something where writing a solution doesn't take too much time, you get a type system, you can brute-force problems, and the usual mind-numbing boring data-manipulation handling fits well into the standard tools.

OCaml is strong too. Stellar type system, fast execution and sane semantics unlike like 99% of all programming languages. If you want to create elegant solutions to problems, it's a good language.

For both, I recommend coming prepared. Set up a scaffold and create a toolbox which matches the typical problems you see in AoC. There's bound to be a 2d grid among the problems, and you need an implementation. If it can handle out-of-bounds access gracefully, things are often much easier, and so on. You don't want to hammer the head against the wall not solving the problem, but solving parsing problems. Having a combinator-parser library already in the project will help, for instance.

It was mind-boggling to see SQL solutions last year: https://news.ycombinator.com/item?id=42577736

My favourite "non-mainstream" languages are, depending on my mood at the time, either:

- Array languages such as K or Uiua. Why they're good for AoC: Great for showing off, no-one else can read your solution (including yourself a few days later), good for earlier days that might not feel as challenging

- Raw-dogging it by creating a Game Boy ROM in ASM (for the Game Boy's 'Z80-ish' Sharp LR35902). Why it's good for AoC: All of the above, you've got too much free time on your hands

Just kidding, I use Clojure or Python, and you can pry itertools from my cold, dead hands.

Clojure works really well for AOC.

A lot of the problems involve manipulating sets and maps, which Clojure makes really straightforward.

I usually do it with ruby with is well suite just like python, but last year I did it with Elixir.

I think it lends itself very well to the problem set, the language is very expressive, the standard library is extensive, you can solve most things functionally with no state at all. Yet, you can use global state for things like memoization without having to rewrite all your functions so that's nice too.

I’ve always used AoC as my jump-off point for new languages. I was thinking about using Gleam this year! I wish I had more profound reasons, but the pipeline syntax is intriguing and I just want to give it a whirl.

I propose Advent of Outage: just pull a random plug in the server room every day.

It's up for me (but the first puzzle won't be available until 15 hours from now).

I am so glad there is no leaderboard this year. Making it a competition really is against the spirit of advent calendars in general. It’s also not a fair competition by default simply due to the issue of time zones and people’s life schedules not revolving around it.

There are plenty of programming competitions and hackathons out there. Let this one simply be a celebration of learning and the enjoyment of problem solving.

Not this time:

> The global leaderboard was one of the largest sources of stress for me, for the infrastructure, and for many users. People took things too seriously, going way outside the spirit of the contest; some people even resorted to things like DDoS attacks. Many people incorrectly concluded that they were somehow worse programmers because their own times didn't compare. What started as a fun feature in 2015 became an ever-growing problem, and so, after ten years of Advent of Code, I removed the global leaderboard.

I mean they're great programming tests, for both people and AI I'd argue - like, it'd be impressive if an AI can come up with a solution in short order, especially with minimal help / prompting / steering. But it wouldn't be a personal achievement, and if it was a competition I'd label it as cheating.

> And yet I expect the whole leaderboard to be full of AI submissions...

There will be no global leaderboard this year.

i don't think there is a global leaderboard this year. just private ones.

Well some people like to code and logic puzzles. And especially as it is in its raw form where you can forget all the noise you encounter while coding professionally with many hoops and responsibilities.

I agree. Didn't these puzzles ruin interviewing for many years now. AI came along and they're still doing it. Some things will needlessly drag on before they die I guess